Infra-red burner



March 28, 1967 P. WOLLNER ETAL 3,311,104

INFRA-RED BURNER Filed Jan. 4, 1965 m '3 lNVENTORS PA UL WOL L NEE ALEXA/V051? QUA YAE 34M Ja ATTORNEYS United States Patent Delaware Filed Jan. 4, 1965, Ser. No. 423,107 4 Claims. (Cl. 126-92) This invention relates to improvements in burners and particularly to burners adapted to emit infra-red rays within contained regions.

Burners which generates radiant energy are important in road surfacing and other operations due to their capacity to provide penetrating heat which does not burn or scorch the surface. Because in the usual case the burners are wholly contained within a structure disposed over the surface to be heated, the heating application is confined to the surface and the material therebelow. It is not only important that the heat penetrate the material without scorching, it is also important that it be uniform within the containing structure, and be directed primarily toward the surface to be heated. According to the present invention there is included in the burner, a specially designed shell which receives the jet flame from the burner in one end and becomes evenly heated throughout the lower part of its length to insure a uniform distribution of the infra-red energy which it generates on being thus heated. The shell is fabricated of one integral piece and serves without separate elements therewithin to provide a constant and uniform source of the radiant heat.

One object of the invention is to provide improvements in infra-red heat generators.

Another object is to provide an infra-red burner which is enabled to apply radiant heat deeply and uniformly to materials.

Other objects and advantages of the invention may be appreciated on reading the following description of one embodiment thereof taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a perspective view of a portable fuel burner made in accordance with the invention;

FIGURE 2 is a longitudinal section of the burner taken on line 2-2 of FIGURE 1;

FIGURE 3 is an end section of the burner taken on line 33 of FIGURE 1;

FIGURE 4 is an enlarged view of the burner shell;

FIGURE 5 is a transverse section taken 'on the line 5-5 of FIGURE 4;

FIGURE 6 is a transverse section taken on the line 66 of FIGURE 4;

FIGURE 7 is a transverse section taken on the line 77 of FIGURE 4; and

FIGURE 8 is a view showing the air and fuel inlet elements of the burner.

Referring to the drawings, a burner is illustrated therein for emitting infra-red heat rays as a heating medium, and, while not limited thereto, the illustrated embodiment is adapted for heating and softening bituminous materials in surfacing operations. The burner includes a housing 14} having an open bottom 11 which is disposed in overlying relation with the materials to be heated. The burner may be moved from place to place by any desired means and for this purpose may be provided with Wheels 12 which are mounted on a cross shaft 13 carried by and located rearwardly of the housing and with the bottom of the wheel disposed above the open side. Thus, the wheels are elevated above the open side or bottom of the housing when the same is in supported relation on the material to be heated. Handles 14 are aflixed to the burner and by depressing the handles the wheels are moved into engagement with the supporting surfacewith 3,311,104 Patented Mar. 28, 1967 the housing elevated thereabove for rolling movement thereof.

The housing is of generally rectangular formation in plan and includes a top wall 15, oppositely disposed flaring side walls 16 and 17, end walls 18 and 19 and with a metal frame 20 of angle iron formation extending about the inner faces of said side and end walls which rims the open side or bottom of the housing.

The side walls 16 and 17 of the housing are longitudinally cut and pressed outwardly to provide a series of longitudinally spaced slits or louvered openings 21 extending into the housing to provide an upward draft of air into the housing therethrough. The top wall 15 is formed with a transversely extending flue opening 23 adjacent the forward end thereof above which is arranged a canopy guard 24 aflixed to the housing at its ends and which guard has its rearward longitudinal edge portion downturned for protection against gusts. of wind entering the housing through the flue opening.

Arranged within the housing are means for emitting infra-red heat rays and for reflecting the same downwardly through the open bottom of the housing. In the present embodiment three such means are provided but it is to be understood that the same may consist of one or more there-of. As illustrated, the said means includes a series of shells 26 extending outwardly from jet burners 27 respectively which are adapted to be connected with a source of hydrocarbon fuel for projecting flames into the tubular shells so as to heat the same from 1200 to 1600 degrees F. or above to emit infra-red heat rays.

The shells 26 are located below and at the foci of parabolic reflectors 28 respectively which reflect the infrared heat rays emitted by the heated shells through the open bottom of the housing. The reflectors 28 taper toward the forward end of the housing for facilitating the flow of the flame jets and flue gases along the length of the shells. The reflectors are affixed to the housing in any desired manner such as by brackets 30 and 31. In the modified embodiment of the invention shown in FIG- URE 3, the reflectors 2811 are flat in cross section. The shells 26 are aflixed in any desired manner to the housing such as by stems 3-2 and rods 33. The stems 32 are aflixed to the end walls 34 which close the outer ends of the shells. The rods 33 also removably support the burners 27.

As shown in FIGURES 3-7, the shells 26 are specially designed to insure uniform distribution over its surface of the generated radiant energy and to emit it primarily toward the surface to be heated. To this end each shell has a cylindrical portion 35 and a reduced portion 36. The reduced portion is formed by causing the upper surface thereof to be channelled as at 33, the depth of the channel progressively increasing from the juncture with the cylindrical portion to the end farthest removed from the burners 27. Compare FIGURES 5 and 6.

The shells have a foraminated lower portion 40 through which the hot flue gases escape into the housing and are discharged through the flue opening 23. The upper portion which is not foraminated remains cooler, especially where it is channelled, whereas the lower portion reaches a uniform temperature throughout its length, thus radiating the major portion of the heat downward to the surface being heated.

The tubes being of stainless steel which has a relatively low heat conductivity, Will permit attaining lower temperatures at the unperforated upper portion and uniform higher temperatures at the foraminated lower portions. The flames are contained within the shells 26 so as to prevent outflow of the flames or impingement thereof against surfaces to be heated. This prevents burning or destroying the bituminous materials when the burner is employed in road surfacing operations.

The jet burners 27 are removably secured in the end wall 19 of the housing with the forward ends thereof extending into the shells and with the burner orifices 40 located inwardly of the end Wall 19. A fuel inlet pipe 41 projects into each of the burners 27 through the wall 42 thereof which wall is formed with air inlets 43 to provide the proper mixture of air with the fuel for supporting combustion. Aflixed to the burners 27 in rearwardly spaced relation from the rear walls 42 thereof are baffles 44 which shield the openings 43 from gusts of Wind which might interfere with the proper burning of the fuel.

While the invention has been illustrated in its application to a burner for emitting infra-red heat rays for use in bituminous surfacing operations, it is to be understood that the invention is not so limited but shall cover and include any and all modifications which fall within the purview of the invention as defined in the following claims.

What is claimed is as follows:

1. In an infra-red burner an elongated hollow shell,

,said shell when horizontally disposed having a lower perforat'ed surface of uniform circumference and cross-section the entire longitudinal length thereof and having a 'longitudinalchannel formed in a portion of its top surface, the depth of said channel progressively increasing along said portion thereof thereby producing along a substantial portion of the length of said shell a progressive reduction in its cross-sectional area without altering the circumference of said perforated surface, and a burner connected with said shell for projecting a flame therein.

2. In an infra-red burner as defined in claim 1, wherein a reflector is disposed above said shell for reflecting the infra-red rays downwardly from said shell.

3. In an infra-red burner as claimed in claim 2, wherein the shape of said reflector is parabolic with the axis of said shell coincident with the focal axis of said reflector.

4. In an infra-red burner as claimed in claim 2, wherein the reflecting surface of said reflector is substantially flat.

References Cited by the Examiner UNITED STATES PATENTS 1,216,848 2/1917 Schmidt 12692 2,051,213 8/1936 Hamilton 12692 2,439,038 4/1948 Cartter 126-92 2,696,369 12/1954 Morley et al 12691 X 2,759,472 8/1956 Cartter 12692 2,985,137 5/1961 Horne 12692 3,187,798 6/1965 Pokorny 12691 X FOREIGN PATENTS 494,087 10/ 1938 Great Britain. v

JAMES W. WESTHAVER, Primary Examiner. 

1. IN AN INFRA-RED BURNER AN ELONGATED HOLLOW SHELL, SAID SHELL WHEN HORIZONTALLY DISPOSED HAVING A LOWER PERFORATED SURFACE OF UNIFORM CIRCUMFERENCE AND CROSS-SECTION THE ENTIRE LONGITUDINAL LENGTH THEREOF AND HAVING A LONGITUDINAL CHANNEL FORMED IN A PORTION OF ITS TOP SURFACE, THE DEPTH OF SAID CHANNEL PROGRESSIVELY INCREASING ALONG SAID PORTION THEREOF THEREBY PRODUCING ALONG A SUBSTANTIAL PORTION OF THE LENGTH OF SAID SHELL A PROGRESSIVE REDUCTION IN ITS CROSS-SECTIONAL AREA WITHOUT ALTERING THE CIRCUMFERENCE OF SAID PERFORATED SURFACE, AND A BURNER CONNECTED WITH SAID SHELL FOR PROJECTING A FLAME THEREIN. 